The overall goal of our studies is to determine the mechanisms by which prenatal availability of choline, and of methyl groups derived from folic acid, modify brain structure and function during development, adulthood and old age. Our principal hypothesis is that the development of the brain during critical periods in embryogenesis is sensitive to changes in maternal diet, specifically to changes in the intake of the essential nutrients, choline and folic acid. We found that rats and mice treated with choline during specific prenatal periods exhibited improvements in memory and attention which lasted throughout their entire lifespan, i.e. supplementation with choline in development prevented age-related memory deterioration. Moreover, variations in maternal choline intake during the second half of pregnancy caused biochemical, structural, and electrophysiologic changes in brain of the offspring. The proposed studies will be conducted with a unified experimental design common to all projects, including the use of mice with targeted mutations in key genes of choline and methyl group metabolism (i.e. apolipoprotein E, methylenetetrahydrofolate reductase, phosphatidylethanolamine N-methyltransferase, and choline dehydrogenase) as models of human conditions associated with polymorphisms in these genes. Dr. Blusztajn (Project 1) will determine if choline availability in utero regulates patterns of gene expression by altering brain DNA methylation and if it alters development and aging of selected neuronal populations identified by gene expression patterns. He will identify the molecular mechanisms of choline action using mutant mouse models. Dr. Meck (Project 2) will determine if altered memory performance in animals exposed to prenatal choline supplementation or deficiency is correlated with changes in sleep patterns, and altered hippocampal ensemble activity patterns. Dr. Williams (Project 3) will determine if prenatal availability of choline influences adult neurogenesis and neuronal survival and will assess behavior in mutant mouse models. Dr. Zeisel (Project 4) will determine the mechanisms by which choline availability alters the patterns of gene expression, cell cycling, migration, apoptosis, and differentiation during fetal development and will study these processes in mutant mouse models. Dr. Kowall (Core B) will provide qualitative and quantitative neuroanatomy analyses using immunohistochemistry and image analysis, and will provide genotyping services for the five projects. The ultimate goal of our studies is to relate our results to the age-associated changes in memory in humans, and to develop perinatal nutritional strategies which could benefit people.